TY - CHAP A1 - Kuhn, Alexander A1 - Engelke, Wito A1 - Flatken, Markus A1 - Hege, Hans-Christian A1 - Hotz, Ingrid T1 - Topology-based Analysis for Multimodal Atmospheric Data of Volcano Eruptions T2 - Topological Methods in Data Analysis and Visualization IV Y1 - 2017 U6 - https://doi.org/10.1007/978-3-319-44684-4_2 SP - 35 EP - 50 PB - Springer CY - Cham, Schweiz ER - TY - JOUR A1 - Kasten, Jens A1 - Reininghaus, Jan A1 - Hotz, Ingrid A1 - Hege, Hans-Christian A1 - Noack, Bernd A1 - Daviller, Guillaume A1 - Morzyński, Marek T1 - Acceleration feature points of unsteady shear flows JF - Archives of Mechanics N2 - A framework is proposed for extracting features in 2D transient flows, based on the acceleration field to ensure Galilean invariance. The minima of the acceleration magnitude, i.e. a superset of the acceleration zeros, are extracted and discriminated into vortices and saddle points --- based on the spectral properties of the velocity Jacobian. The extraction of topological features is performed with purely combinatorial algorithms from discrete computational topology. The feature points are prioritized with persistence, as a physically meaningful importance measure. These features are tracked in time with a robust algorithm for tracking features. Thus a space-time hierarchy of the minima is built and vortex merging events are detected. The acceleration feature extraction strategy is applied to three two-dimensional shear flows: (1) an incompressible periodic cylinder wake, (2) an incompressible planar mixing layer and (3) a weakly compressible planar jet. The vortex-like acceleration feature points are shown to be well aligned with acceleration zeros, maxima of the vorticity magnitude, minima of pressure field and minima of λ2. Y1 - 2016 VL - 68 IS - 1 SP - 55 EP - 80 ER - TY - GEN A1 - Kuhn, Alexander A1 - Engelke, Wito A1 - Flatken, Markus A1 - Hege, Hans-Christian A1 - Hotz, Ingrid T1 - Topology-based Analysis for Multimodal Atmospheric Data of Volcano Eruptions N2 - Many scientific applications deal with data from a multitude of different sources, e.g., measurements, imaging and simulations. Each source provides an additional perspective on the phenomenon of interest, but also comes with specific limitations, e.g. regarding accuracy, spatial and temporal availability. Effectively combining and analyzing such multimodal and partially incomplete data of limited accuracy in an integrated way is challenging. In this work, we outline an approach for an integrated analysis and visualization of the atmospheric impact of volcano eruptions. The data sets comprise observation and imaging data from satellites as well as results from numerical particle simulations. To analyze the clouds from the volcano eruption in the spatiotemporal domain we apply topological methods. Extremal structures reveal structures in the data that support clustering and comparison. We further discuss the robustness of those methods with respect to different properties of the data and different parameter setups. Finally we outline open challenges for the effective integrated visualization using topological methods. T3 - ZIB-Report - 16-03 KW - multi-modal, intergrated data analysis, topology Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-57043 SN - 1438-0064 ER - TY - GEN A1 - Kasten, Jens A1 - Reininghaus, Jan A1 - Hotz, Ingrid A1 - Hege, Hans-Christian A1 - Noack, Bernd A1 - Daviller, Guillaume A1 - Morzyński, Marek T1 - Acceleration feature points of unsteady shear flows N2 - A framework is proposed for extracting features in 2D transient flows, based on the acceleration field to ensure Galilean invariance. The minima of the acceleration magnitude, i.e. a superset of the acceleration zeros, are extracted and discriminated into vortices and saddle points --- based on the spectral properties of the velocity Jacobian. The extraction of topological features is performed with purely combinatorial algorithms from discrete computational topology. The feature points are prioritized with persistence, as a physically meaningful importance measure. These features are tracked in time with a robust algorithm for tracking features. Thus a space-time hierarchy of the minima is built and vortex merging events are detected. The acceleration feature extraction strategy is applied to three two-dimensional shear flows: (1) an incompressible periodic cylinder wake, (2) an incompressible planar mixing layer and (3) a weakly compressible planar jet. The vortex-like acceleration feature points are shown to be well aligned with acceleration zeros, maxima of the vorticity magnitude, minima of pressure field and minima of λ2. T3 - ZIB-Report - 15-65 Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-58397 SN - 1438-0064 ER - TY - CHAP A1 - Engelke, Wito A1 - Kuhn, Alexander A1 - Flatken, Markus A1 - Chen, Fang A1 - Hege, Hans-Christian A1 - Gerndt, Andreas A1 - Hotz, Ingrid T1 - Atmospheric Impact of Volcano Eruptions T2 - Proceedings IEEE SciVis 2014 N2 - The analysis of data that captures volcanic eruptions and their atmospheric aftermath plays an important role for domain experts to gain a deeper understanding of the volcanic eruption and their consequences for atmosphere, climate and air traffic. Thereby, one major challenge is to extract and combine the essential information, which is spread over various, mostly sparse data sources. This requires a careful integration of each data set with its strength and limitations. The sparse, but more reliable measurement data is mainly used to calibrate the more dense simulation data. This work combines a collection of visualization approaches into an exploitative framework. The goal is to support the domain experts to build a complete picture of the situation. But it is also important to understand the individual data sources, the wealth of their information and the quality of the simulation results. All presented methods are designed for direct interaction with the data from different perspectives rather than the sole generation of some final images. Y1 - 2014 ER - TY - CHAP A1 - Kratz, Andrea A1 - Schöneich, Marc A1 - Zobel, Valentin A1 - Burgeth, Bernhard A1 - Scheuermann, Gerik A1 - Hotz, Ingrid A1 - Stommel, Markus T1 - Tensor Visualization Driven Mechanical Component Design T2 - Proc. IEEE Pacific Visualization Symposium 2014 Y1 - 2014 U6 - https://doi.org/10.1109/PacificVis.2014.51 SP - 145 EP - 152 ER - TY - JOUR A1 - Schöneich, Marc A1 - Stommel, Markus A1 - Kratz, Andrea A1 - Zobel, Valentin A1 - Scheuermann, Gerik A1 - Hotz, Ingrid A1 - Burgeth, Bernhard T1 - Optimization strategy for the design of ribbed plastic components JF - International Journal of Plastics Technology Y1 - 2014 IS - 10 SP - 160 EP - 175 ER - TY - JOUR A1 - Kratz, Andrea A1 - Baum, Daniel A1 - Hotz, Ingrid T1 - Anisotropic Sampling of Planar and Two-Manifold Domains for Texture Generation and Glyph Distribution JF - Transactions on Visualization and Computer Graphics (TVCG) Y1 - 2013 U6 - https://doi.org/10.1109/TVCG.2013.83 VL - 19 SP - 1782 EP - 1794 ER - TY - JOUR A1 - Kratz, Andrea A1 - Auer, Cornelia A1 - Stommel, Markus A1 - Hotz, Ingrid T1 - Visualization and Analysis of Second-Order Tensors: Moving Beyond the Symmetric Positive-Definite Case JF - Computer Graphics Forum - State of the Art Reports Y1 - 2013 U6 - https://doi.org/10.1111/j.1467-8659.2012.03231.x VL - 1 SP - 49 EP - 74 ER - TY - GEN A1 - Zobel, Valentin A1 - Reininghaus, Jan A1 - Hotz, Ingrid T1 - Visualization of Two-Dimensional Symmetric Tensor Fields Using the Heat Kernel Signature T2 - Topological Methods in Data Analysis and Visualization III Y1 - 2013 SP - 249 EP - 262 CY - Davis, CA, USA ER -